The present invention relates to an elevator control apparatus in which reversion floors of elevator cages can be predicted accurately.
Heretofore, a group control operation has been generally employed in an elevator apparatus having a plurality of cages provided side by side. As an example of the group control operation, there is an assignment system. The assignment system is such that an estimated value for each cage is calculated immediately after registration of a landing-place call, and a cage having the best estimated value is selected as an assigned cage to perform service so that only the assigned cage is made to respond to the landing-place call, thereby improving running efficiency and shortening the waiting time. In the calculation of such an estimated value, in general, predicted waiting time for the landing-place call has been used. For example, in an elevator group-control apparatus described in Published Examined Japanese Patent Application No. Sho-58-48464, the sum of the squares of all values of predicted waiting time for all landing-place calls is calculated as an estimated value for each cage on the assumption that the landing-place calls are temporarily assigned to the respective cages when the landing- place calls are registered, by which a cage having the minimum estimated value is selected as an assigned cage.
In this case, the predicted waiting time is calculated by adding the landing-place call duration (the time elapsed after a landing-place call was registered) to the predicted arrival time (the time required for the car to move from the present position to the floor where the landing-place call has been issued).
The waiting time for the landing-place call can be shortened (in particular, the long waiting time of a minute or more can be reduced) by using the estimated value thus obtained.
If the predicted arrival time is not accurate, the estimated value cannot have the meaning of a reference value for selection of the assigned cage so that the waiting time for the landing- place call cannot be shortened. Accordingly, the accuracy of the predicted arrival time has a great influence on the performance of the group control.
In the following, conventional predicted arrival time calculation methods are described specifically. The predicted arrival time is calculated in such a manner (A) as follows on the assumption that the cage makes a reciprocating motion between two end floors.
(A) The time required for running (running time) is calculated from the distance between the cage position and the target floor, the time required for stopping (stop time) is calculated from the number of stops at intermediate floors between the cage position and the target floor, and the predicted arrival time is calculated by adding the running time to the stop time (Refer to Published Examined Japanese Patent Application No. Sho-54-20742 and Published Examined Japanese Patent Application No. Sho-54-34978).
To improve the accuracy in prediction of the stop time at the cage-position floor and the stop-expected floors, the following prediction methods (B)-(E) have been proposed. (B) Correction is made on the predicted arrival time in accordance with the cage state (in the deceleration, in the door- opening operation, in the opened-door state, in the door-closing operation, in the running state, etc.) at the floor where the cage is present (Refer to Published Examined Japanese Patent Application No. Sho-57-40074).
(C) The number of passengers getting on and the number of passengers getting off at each stop-expected floor are detected by using a detection or prediction device, and correction is made on the predicted arrival time in accordance with the number of those passengers (Refer to Published Examined Japanese Patent Application No. Sho-57-40072 and Published Unexamined Japanese Patent Application No. Sho-58-162472).
(D) Correction is made on the predicted arrival time on the consideration of the fact that the time required for passengers to enter and exit a cage varies depending on whether the stop-expected floor is selected due to a cage call or to a landing place call (Refer to Published Examined Japanese Patent Application No. Sho-57-40072).
(E) The stop time at each floor is predicted on the basis of statistical data obtained by measuring the true stop time door- opening time, passenger-entry and exit time and door-closing time) at each floor or on the basis of door open time obtained by simulation and built in the group controller (Refer to Published Unexamined Japanese Patent Application No. Hei-1-275382 and Published Unexamined Japanese Patent Application No. Sho-59-138579).
To improve the predicted arrival time on the consideration of the possibility that a call will be registered in the future to stop the cage at a stop-unexpected floor, the following methods (F)-(H) have been proposed further.
(F) The number of cage calls to be produced by the stopping of the cage to respond to a landing-place call at intermediate floors is predicted on the basis of statistical data pertaining to the number of passengers in the past, and the predicted number of cage calls is distributed to the forward floors on the basis of the statistical probability distribution of cage calls which occurred in the past to thereby predict the stop time due to the derivative cage calls (Refer to Published Examined Japanese Patent Application No. Sho-63-34111).
(G) The probability of stopping of the cage at each floor and at each cage direction is calculated on the basis of the number of times of cage direction reversal and the measured value of the number of passengers in each cage direction in the past, and correction is made on the predicted arrival time on the basis of the result of the above calculation (Refer to Published Unexamined Japanese Patent Application No. Sho-59-26872).
(H) The stop time due to the cage call at each floor is predicted on the basis of the floor getting-off rate calculated for each floor and for each direction (Refer to Published Examined Japanese Patent Application No. Sho-63-64383).
As described above, it is general in the prior art that the predicted arrival time is calculated on the assumption that the cage makes a reciprocating motion between the two end floors. However, in most cases, the direction of the movement of the cage is reversed at an intermediate floor by maximum call reversion or minimum call reversion. There arises a problem in that an error is produced between the predicted arrival time and the true arrival time.
To solve this problem, a method of calculating the elevator service predicted time has been proposed as described in Published Examined Japanese Patent Application No. Sho-54-16293. In the calculation method, the running time to a call floor at a greatest distance in the direction of the movement of the cage and the running time to a call floor in the reverse direction therefrom are calculated to calculate the predicted arrival time. According to the calculation method, a floor URF (upper reversion floor) where the direction of the cage is reversed at the maximum call and a floor LRF (lower reversion floor) where the direction of the movement of the cage is reversed at the minimum call are set respectively to the uppermost floor among the cage call or landing-place call floors and to the lowermost floor among the cage call or landing place call floors.
However, it has been found that the aforementioned upper and lower reversion floor setting method has still a problem in the point of accuracy in the predicted arrival time. This point will be described with reference to FIG. 8.
In the drawing, the reference numeral (1) designates an elevator cage which is operated between the 1st floor and the 12th floor. The reference numeral (8c) designates a cage call at the 8th floor, (7d) and (9d) respectively designate downward landing-place calls at the 7th and 9th floors, and (7u) and (9u) respectively designate upward landing-place calls at the 7th and 9th floors.
The upper reversion floor URF in each of conditions (a)-(f) in FIG. 8 is set to the uppermost floor among the cage call or landing-place call floors. That is, as shown in the drawing, URF is set to 8F, 9F, 9F, 8F, 9F and 9F in the conditions (a)-(f) respectively.
In each of the conditions (c) and (f), however, the upper reversion floor URF is set to the 9th floor 9F of the upward landing-place call (9u) though it can be sufficiently expected that a new cage call may be registered at a floor above 9F after the cage (1) has responded to the upward landing-place call (9u) at 9F. In this case, it is irrational that the upper reversion floor URF is set to 9F. That is, in this case, the upper reversion floor ought to be set to any floor of 10F or higher.
Considering cage calls derived when response is made to the upward landing-place call (7u) at 7F, in the condition (d), it is similarly obvious that error with respect to the predicted arrival time becomes large when the upper reversion floor URF in the condition (d) is set to 8F. Also in each of the conditions (a) and (b), the possibility that the upper reversion floor URF may be shifted more upward by assigning a new landing-place call to the upward moving cage is sufficiently considered according to the traffic circumstances.
In general, the predicted reversion floor is used for prediction of in-cage crowdedness, prediction of near-future cage position, prediction of cage settlement, etc. as well as it is used for calculation of the predicted arrival time to carry out the dispersive waiting operation of a plurality of cages, the assignment operation for landing-place calls, etc. Accordingly, accuracy in prediction of the reversion floor has a great influence on accuracy in other various kinds of prediction.
Further, a group-control controller for selecting a cage assigned a landing-place call on the basis of calculation using a neural network imitating the neuron of the human brain has been proposed as described in Published Unexamined Japanese Patent Application No. Hei-1-275381. However, there is no consideration of improvement in accuracy in calculation of the predicted arrival time and accuracy in calculation of the predicted in-cage crowdedness.
As described above, the conventional elevator control apparatuses have a problem in that reversion floors can not be predicted so accurately that a large error with respect to the predicted arrival time is produced, because there is no consideration of the possibility that calls will occur in the near future.